Biology Reference
In-Depth Information
13.
Adaptation of Native
Herbivores to Alien Plants
“An ecological genetics approach to the study of herbivorous insects has
revealed highly significant genetic variation in characters associated with host
plant exploitation. In some cases, as much variability can be seen within
single populations as within the species as a whole. In other cases, populations
are highly locally adapted to different host plants.”
—V
IA
(1990)
In western Nevada, Edith's checkerspot butterfly (
Euphydryas editha
)
occurs in isolated populations where various native plant hosts are avail-
able. At Schneider's Meadow in the Sierra Nevadas of Esmeralda County,
the native host plant is
Collinsia parviflora
,a member of the figwort fam-
ily (Scrophulariaceae). With the advent of cattle ranching to the moun-
tain country, ribwort plantain (
Plantago lanceolata
), belonging to the plan-
tain family (Plantaginaceae), became a prominent member of the meadow
plant community. This European broad-leafed herb has become almost
ubiquitous in meadow and disturbed grassland habitats throughout North
America.
At Schneider's Meadow, Edith's checkerspot began to lay eggs on rib-
wort plantain when it appeared (Thomas et al. 1987). Checkerspots from
populations in areas without ribwort plantain, in fact, contain about 10%
of individuals that accept ribwort plantain as readily as
Collinsia
(Singer et
al. 1993). At Schneider's Meadow, however, the oviposition preference for
ribwort plantain increased from less then 10% in 1982 to more than 50%
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